The present application relates to a cooling system and, more particularly, an apparatus and method for cooling an electronic device.
Electronic devices typically generate large amounts of heat during operation. Such devices may include power supplies, personal computers, servers, power converters for hybrid vehicles, start-stop generators and various automotive systems. If this heat cannot be effectively removed, temperatures may rise to levels that prevent normal function, possibly leading to failure. This issue is especially relevant for electronic devices operating in high temperature environments, such as near the engine of an automobile.
Heat may be transferred from an electronic device by conduction, radiation, evaporation, convection or some combination of these mechanisms. Convection typically refers to a circulating fluid (e.g., a liquid or gas) that absorbs and carries away heat from the surface of an object.
Convective cooling may be implemented as an open loop system or a closed loop system. In an open loop system, the moving fluid absorbs heat and then is discarded and replaced with fresh fluid. In a closed loop system, a circulating fluid flows over a hot surface, passes through a heat exchanger to cool the fluid, and then is recirculated to the hot surface.
An integrated circuit, such as a flip chip, may be cooled using convective cooling, as described in U.S. Ser. No. 10/919,168, the entire contents of which are incorporated herein by reference. Specifically, the flip chip may be attached to a printed circuit board and may include a plurality of microchannels on a surface thereof. A tiny cap may be attached to the circuit board to enclose the flip chip therebetween and form a fluid containment around the flip chip. A cooling fluid may be passed through the fluid containment such that the fluid passes over the microchannels to cool the flip chip.
Unfortunately, a significant portion of the cooling fluid may bypass the microchannels and, instead, flow through a gap between the inside of the cap and the top and sides of the chip, thereby reducing the heat transfer from the chip to the cooling fluid. Such gaps are practically unavoidable given the required tolerances for assembling such components.
Accordingly, there is a need for a fluid-cooled electronic system for directing cooling fluid into the microchannels of an electronic device, thereby by improving the heat transfer between the electronic device and the cooling fluid.